CVE-2025-61622 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in pyfory. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for pyfory — see the affected versions and patch details below.
Apache Fory, Apache Fory: Python RCE via unguarded pickle fallback serializer in pyfory
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-61622.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
pyfory🐍pyfuryReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Deserialization of untrusted data in python in pyfory versions 0.12.0 through 0.12.2, or the legacy pyfury versions from 0.1.0 through 0.10.3: allows arbitrary code execution. An application is vulnerable if it reads pyfory serialized data from untrusted sources. An attacker can craft a data stream that selects pickle-fallback serializer during deserialization, leading to the execution of pickle.loads, which is vulnerable to remote code execution.
Users are recommended to upgrade to pyfory version 0.12.3 or later, which has removed pickle fallback serializer and thus fixes this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyfory | ≥ 0.12.0&&< 0.12.3 | 0.12.3pip install --upgrade 'pyfory==0.12.3' |
| 🐍PyPI | pyfury | ≥ 0.1.0 | No fix |
Affected Products
foryapacheResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyfory, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pyfory to 0.12.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-61622 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Frequently Asked Questions
Is CVE-2025-61622 in your dependencies?
Find it across PyPI, including transitive dependencies.